KR101161585B1 - Data transferring system and method using network coding - Google Patents

Abstract

The present invention is a security processing system in a network using network coding that collects packets transmitted from a transmitting node at an intermediate node and then encodes and transmits the packets to the receiving node. To this end, according to an embodiment of the present invention, After generating a secure channel with the receiving node, the channel forming unit sharing the security key with the receiving node, and the transmission data to be transmitted to the receiving node divided into blocks and encrypts each block to generate a transmission packet, And a data processor for transmitting the calculated checksum value to the receiving node after calculating each checksum value for each of the blocks, and a transmitting unit for transmitting the generated transmission packet to the receiving node through an intermediate node. Calculates the checksum value for the transmission packet received from the transmitting node and then receives the calculated checksum value and the receiving node. Through a comparison of a checksum value to check the integrity of the received transport packet.

Description

Data transmission system and method in network using network coding {DATA TRANSFERRING SYSTEM AND METHOD USING NETWORK CODING}

The present invention relates to data transmission in a network using network coding. More particularly, the present invention relates to a checksum value of a packet calculated through a linear operation after receiving a packet transmitted from a transmitting node using network coding, and to a transmitting node. The present invention relates to a data transmission system and method in a network using network coding that can check the integrity of a packet through comparison between checksum values received from the system.

In general, network coding is a new network paradigm that is different from the existing method of transmitting data by encoding data at a transmitting node and an intermediate node. The receiving node of the network coding collects and re-encodes incoming data from the intermediate node through all the outgoing links and receives them through various paths, and then collects and decodes the encoded data at the transmitting node. Get the sent data. Here, a problem arises that is different from the general transmission method of transmitting data to a desired receiving node through existing routing.

First, all nodes other than the intended receiving node at the sending node receive the data, and even if the node is not desired, confidentiality is not guaranteed because the receiving node can decode the data after receiving a certain amount of data. There is a problem.

Another problem of network coding is that the transmitted data is different from the data sent by the transmitting node. In other words, the integrity problem may always occur because network coding re-encodes and receives the packets received by the intermediate nodes.

In addition, as a factor of lowering the decoding rate of the receiving node, a transmission error occurring in the data transmission and a bogus packet may be injected intentionally, thereby preventing the decoding of the receiving side. In the case of a network using network coding, the decoding rate of the receiving node is one of the important factors affecting the network performance. To solve this problem, forward-error-correction technique can be used. In this case, however, redundancy bit should be added when transmitting data at the sending node for error recovery. Let's do it. In addition, since the overhead of the receiving node for error recovery is sharply increased, it is not suitable for network coding that needs to receive and decode a certain amount of data quickly.

In order to solve the above problems, an object of the present invention is to provide a data transmission system in a network using a network coding that can discard an error packet by checking the integrity immediately upon receiving data using a block-based checksum and To provide a method.

The present invention also provides a data transmission system and method in a network using network coding that encrypts a block unit, which is a basic unit of data transmission, through a block encryption scheme.

The present invention provides a system and method for transmitting data in a network using network coding that can share one security key through a security channel formed between a receiving node and a transmitting node to ensure integrity and confidentiality.

The objects of the present invention are not limited to the above-mentioned objects, and other objects not mentioned can be clearly understood by those skilled in the art from the following description.

In order to achieve the object of the present invention, a data transmission system in a network coding network according to an embodiment of the present invention collects packets transmitted from a transmitting node in an intermediate node, encodes the packets, and transmits the encoded data to the receiving node. A security processing system in a used network, wherein the transmitting node comprises a channel forming unit which shares a security key with the receiving node after forming a secure channel with the receiving node, and transmits data to be transmitted to the receiving node. A data processing unit for generating a transmission packet by encrypting each block after dividing it into blocks, calculating a checksum value for each encrypted block, and transmitting the calculated checksum value to the receiving node, and the generated transmission. A transmitter for transmitting a packet to the receiving node through the intermediate node, wherein the receiving node After checking the checksum value for the transport packet received from the transmitting node, the integrity check of the received transport packet is checked through a comparison between the calculated checksum value and the checksum value received from the transmitting node.

In the data transmission system in a network coding network according to an embodiment of the present invention, the data processing unit calculates the max-flow value in consideration of the network situation, and then converts the max-flow value into a block size that is a basic unit of transmission. And a transmission packet generation unit configured to generate the transmission packet by dividing the transmission data into the block to fit the set block size and encrypting each of the blocks with the security key.

In the data transmission system in the network coding network according to an embodiment of the present invention, the data processing unit calculates a value for each bit through the security key and the operation of the data of each bit in the encrypted block, the calculation And a checksum calculator for generating a total checksum value for the transport packet by calculating a checksum value for each of the blocks after summing the values for each bit, and transmitting the total checksum value to the receiving node.

In a data transmission system in a network coding network according to an embodiment of the present invention, the receiving node may determine a linear operation value between actual data and the security key in the received transmission packet and coding information of intermediate nodes through which the transmission packet passes. The integrity check may be performed by comparing a linear operation value between a global encoding vector having a value and a checksum value received from the transmitting node.

In a data transmission system in a network coding network according to an embodiment of the present invention, the receiving node may ignore a packet in which an error occurs as a result of the integrity check and perform decoding using only packets without errors. .

In a data transmission system in a network coding network according to an embodiment of the present invention, when the receiving node has a predetermined number or more, the receiving node receives information about the packet in which the error occurs through the secure channel. After transmitting to the transmitting node and receiving a block corresponding to the information from the transmitting node through the secure channel, it can be used for decoding.

In a data transmission system in a network coding network according to an embodiment of the present invention, the transmitting node encrypts a block corresponding to the information in the transmitting node using the security key and transmits the same to the receiving node. Can be.

In a data transmission system in a network coding network according to an embodiment of the present invention, the receiving node may decode the encrypted block received from the transmitting node with the security key and then decode the decrypted block. have.

In another aspect, a data transmission method in a network coding network according to an embodiment of the present invention collects packets transmitted from a transmitting node at an intermediate node, encodes the data, and transmits the data to the receiving node. A transmission method comprising the steps of: sharing a security key by establishing a secure channel between the transmitting node and the receiving node, dividing the transmission data into blocks at the transmitting node, and encrypting each block to generate a transmission packet; Calculating a checksum value for each encrypted block, and transmitting the calculated checksum value to the receiving node, and transmitting the generated transmission packet to the receiving node through the intermediate node. And calculating a checksum value for the transport packet received at the receiving node. Through a comparison of the checksum value with a checksum value received from the transmitting node comprises the steps of checking the integrity of the received transport packet.

In the data transmission method in a network coding network according to an embodiment of the present invention, generating the transport packet may include calculating a max-flow value in consideration of the network situation, and transmitting the calculated max-flow value. The method may include setting a block size that is a basic unit of, dividing the transmission data into the blocks so as to correspond to the set block size, and encrypting each of the blocks to generate the transport packet.

In the data transmission method in a network coding network according to an embodiment of the present invention, the performing the integrity check may include: determining a first value through a linear operation between actual data and the security key in a transmission packet received at the receiving node; Calculating a second value through a linear operation between a global encoding vector having coding information of intermediate nodes passing through the transport packet and a checksum value received from the transmitting node, and calculating the first value and the second value. And performing the integrity check by comparing the two values.

In the data transmission method in the network coding network according to an embodiment of the present invention, the step of transmitting to the receiving node, the data of each bit in the encrypted block through the security key and the operation for the value of each bit After calculating, summing the calculated values for each bit and calculating a checksum value for each of the blocks, a total checksum value for the transport packet may be generated and transmitted to the receiving node.

The data transmission method in a network coding network according to an embodiment of the present invention further includes the step of ignoring a packet in which an error occurs according to the integrity check result at the receiving node, and decoding using only packets without errors. can do.

In a data coding method in a network coding network according to an exemplary embodiment of the present invention, when the number of packets in which an error occurs is greater than or equal to a predetermined number, transmitting information on the block that cannot be decoded to the transmitting node through the secure channel. And receiving a block corresponding to the information from the transmitting node through the secure channel and decoding the same.

In the method of transmitting data in a network coding network according to an embodiment of the present invention, the step of receiving the data through the secure channel and then decoding the received data includes encrypting a block corresponding to the information at the transmitting node using the security key. Thereafter, the method may include transmitting the same to the receiving node, decrypting the encrypted block received at the receiving node with the security key, and decoding the decrypted block.

According to the present invention, after transmitting and encrypting transmission data into a plurality of blocks by using a security key shared through a security channel between transmitting and receiving nodes, a checksum value for each encrypted block is calculated and transmitted to the receiving node, and the receiving node. After receiving the packet sent from the sending node by using network coding, the integrity of the packet is checked by comparing the checksum value of the packet calculated through linear operation with the checksum value received through the secure channel from the sending node. However, there is an effect of ensuring confidentiality and integrity in transmitting data using network coding.

1 is a block diagram illustrating a data transmission system in a network using network coding according to an embodiment of the present invention.
2 is a diagram illustrating a process of generating a transport packet by dividing the transport data into blocks according to an embodiment of the present invention.
3 is a diagram illustrating a process of calculating a checksum value for a transport packet of each encrypted block according to an embodiment of the present invention.
4 is a flowchart illustrating a data transmission process in a network configuration using network coding according to an embodiment of the present invention.

The objects and effects of the present invention and the technical configurations for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. The following terms are defined in consideration of the functions of the present invention, and may be changed according to the intentions or customs of the user, the operator, and the like.

The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. The present embodiments are merely provided to complete the disclosure of the present invention and to fully inform the scope of the invention to those skilled in the art, and the present invention is defined by the scope of the claims. It will be. Therefore, the definition should be based on the contents throughout this specification.

In an embodiment of the present invention, after transmitting and encrypting the transmission data into a plurality of blocks using a security key shared through a secure channel between the transmitting and receiving nodes, the checksum value for each encrypted block is calculated and transmitted to the receiving node. After receiving the packet sent from the sending node by using network coding at the receiving node, the integrity of the packet is compared by comparing the checksum value of the packet calculated through linear operation with the checksum value received through the secure channel from the transmitting node. A data transmission system and method in a network using a network coding that can check the present invention are described.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram illustrating a data transmission system in a network using network coding according to an exemplary embodiment of the present invention, which includes a transmitting node 100, an intermediate node 120, a receiving node 140, and the like. Can be. The transmitting node 100 may include a channel forming unit 102, a data processing unit 104, a transmission unit 106, and the like, and the data processing unit 104 may include a transmission packet generator 104a and a checksum calculator ( 104b) and the like.

The channel forming unit 102 of the transmitting node 100 forms a secure channel with the receiving node 140 and then shares the security key and checksum value using the secure channel, and decodes the receiving node 140. Receive additional data requests as needed.

The data processing unit 104 of the transmitting node 100 calculates the max-flow value in consideration of the network situation up to the receiving node 140 in order to transmit data using network coding, and then calculates the max-flow value based on the basic unit of transmission. The block size is determined, and the transmission data is divided into blocks according to the determined block size.

In addition, the transport packet generator 104a of the data processor 104 generates a transport packet by dividing the data to be transmitted into blocks and encrypting the data with a security key, which will be described below.

First, data to be transmitted according to a block size is divided into h blocks (b ₁ , b ₂ , b ₃ ,..., B _n-1 , b _n ) as shown in FIG. It consists of n bits. Here, as each block is encrypted, the first block b ₁ of data to be transmitted is X _1,1 , X _1,2 , X _1,3 ,... _Which are encrypted information 200. … , X _{1, n} , and the h th block (b _n ) is X _{h, 1} , X _{h, 2} , X _{h, 3} ,... … , X _{h, N} In addition, in addition to the encrypted information 200, a h-bit global encoding vector 210 is added to each block. Through this process, each encrypted block is composed of a transport packet consisting of a global encoding vector 210 of h bits and information 200 of encrypted n bits.

The checksum calculator 104b of the data processor 104 calculates a checksum value for the transport packet of each encrypted block and transmits the calculated checksum value to the receiving node 140.

A process in which the transmitting node 100 calculates a checksum value for a transmission packet of each encrypted block will be described with reference to FIG. 3.

3, the angle of the inside the encrypted block encryption information 200 bits and a secret key in addition one of the result of each bit multiplied by the (k _1, k _2, k _3, ..., k _N) Compute the checksum value (SKC ₁ ) for the block. In this way, the checksum value for each encrypted block is calculated, and the checksum values are collected to generate a total checksum value (SKC) for the data to be transmitted. That is, the result of multiplying X _1,1 by the encryption key (k ₁ ), the result of multiplying X _1,2 by the encryption key (k ₂ ), the result of multiplying X _1,3 by the encryption key (k ₃ ), … … Compute the checksum value (SKC ₁ ) for the first encrypted block by calculating the result of multiplying X _{1, N} by the encryption key (k _N ) and adding each result. In this way, the total checksum SKC can be calculated by calculating the checksum value SKC _h up to the h-th block.

Here, the encryption key (k = k ₁ , k ₂ , k ₃ , ..., k _N ) is a security key shared by the transmitting and receiving nodes 100 and 140 through a transmission channel, and is the i-th n-th bit of encrypted information. When the block X _i is "[X _{i, 1} ,..., X _{i, N} ]", the checksum SKC _i of the i th block X _i for integrity checking may be represented by Equation 1 below.

[Equation 1]

Through this process, the transmitting node 100 may calculate a checksum value for all data divided into h blocks, that is, a total checksum value (SKC = [SKC ₁ … SKC _h ]), and the calculated total checksum value By transmitting the (SKC) to the receiving node 140 through the secure channel of the channel forming unit 102 and the receiving node 140 before data transmission, the receiving node 140 receives the received packet immediately after receiving the packet. Integrity checks can be performed.

The transmission unit 106 transmits the transmission packet generated by the transmission packet generator 104a to the receiving node 140 through the intermediate node 120. The transmission packet corresponding to the transmission data is transmitted using practical network coding. In the case of transmission, the packet transmitted to the receiving node 140 through the coding of the intermediate nodes 120 is a global encoding vector g (e) having coding information of the intermediate nodes 120 and y (( e)) is displayed continuously, as shown in Equation 2 below.

[Equation 2]

When the receiving node 140 receives the data, the received packet is immediately calculated using a linear operation, and then the channel forming unit 102 is transmitted before the checksum and the transmitting node 100 transmit the transmitted packet. Integrity is checked through comparison between the checksum values transmitted through the secure channel of the receiving node 140 and ignores packets with errors as a result of the check, and receives only packets without errors and uses them for decoding.

The integrity check process at the receiving node 140 may be defined by Equation 3 below.

&Quot; (3) "

As shown in Equation 3 above, when the receiving node 140 receives the data y (e), K? Y (which is a linear operation of the security key K and the actual data y (e)) is received. e) Integrity is checked by comparing the checksum value, which is a value, and the SKC? g (e), a linear operation value of the global encoding vector.

The vector operation value of the security key K and the received data (y (e)) is equal to the vector operation value of the checksum value SKC and the received global encoding vector g (e). Prove that.

&Quot; (4) "

The receiving node 140 may receive a sufficient amount of packets necessary for decoding except for packets in which an error occurs after a predetermined time due to the characteristics of network coding. For this reason, data that is discarded through integrity check can be decoded.

On the other hand, the receiving node 140 can not be decoded when the network state is bad or there are a lot of inappropriate packets injected malicious by any user, that is, more than a predetermined number of packets can be ignored in the integrity check, in this case secure channel Through this, the transmitting node 100 sends information about a block that cannot be decoded, that is, a transport packet that is ignored through integrity check. Accordingly, the transmitting node 100 encrypts a block corresponding to the information received from the receiving node 140 using the security key and transmits the block to the receiving node 140 through the secure channel.

When a sufficient amount of data for decoding is received, the receiving node 140 decodes the corresponding block, and decrypts the encrypted data using the security key received from the transmitting node 100 before receiving the data.

A process of data transmission in a network configuration using network coding having the above configuration will be described with reference to FIG. 4.

4 is a flowchart illustrating a data transmission process in a network configuration using network coding according to an embodiment of the present invention.

Referring to FIG. 4, the transmitting node 100, which is a source node, forms a secure channel with the receiving node 140 to share a security key (S400).

Then, the transmitting node 100 transmits the security key to the receiving node 140 through the secure channel, thereby sharing the security key between the transmitting node 100 and the receiving node 140 (S402).

Thereafter, the transmitting node 100 calculates the max-flow value in consideration of the network situation up to the receiving node in order to transmit the transmission data using network coding (S404). In this case, the calculated max-flow value is used to determine a block size that is a basic unit of transmission, that is, the transmission data is divided into a plurality of blocks using the max-flow value (S406).

Then, the transmitting node 100 performs encryption on each block (S408), calculates a checksum value for each encrypted block, and transmits the outgoing checksum value to the receiving node 140 (S410). ).

Then, the transmitting node 100 transmits each encrypted block to the receiving node 140 via the intermediate node 120 (S412), where the transmitting node 100 globally encodes each encrypted block. When one packet is added by adding a vector and then transmitted using practical network coding, the packet transmitted to the receiving node 140 through the coding of the intermediate nodes 120 has coding information of the intermediate nodes 120. The y (e) having the global encoding information and the actual data can be displayed successively.

When the receiving node 140 receives data, the received packets are calculated using a linear operation (S414), and the calculated checksum values are transmitted before the transmitting node 100 transmits the transmission data. Integrity is checked through a comparison between one checksum value (S414).

As a result of the check in S414, the receiving node 140 ignores the packet in error (S416), receives only the packet without an error, and classifies the packet to be used for decoding (S418).

On the other hand, the receiving node 140 determines whether the amount of packets required for decoding for a predetermined time has been received (S420), if the amount of packets required for decoding for a predetermined time is not received, i.e. If more than a predetermined number of packets are ignored during the integrity check, information about a block that cannot be decoded is transmitted to the transmitting node 100 through a secure channel (S422). Accordingly, the transmitting node 100 encrypts the blocks corresponding to the information about the block that cannot be decoded and transmits the blocks to the receiving node 140 through the secure channel, and the receiving node 140 transmits the secure channel. After decrypting the block received through the security key (S424), the process proceeds to S420 to perform a subsequent step.

As a result of the determination of S420, when the amount of packets required for decoding for a predetermined time is received, the receiving node 140 decodes using the received packets (packets without error) (S426).

According to an embodiment of the present invention, the transmission data is divided into a plurality of blocks by using a security key shared through a secure channel between the transmitting and receiving nodes 100 and 140, and then a checksum value is calculated for each encrypted block. The packet is transmitted to the receiving node 140, the receiving node 140 receives the packet transmitted from the transmitting node 100 using network coding, and then calculates a checksum value for the received packet through linear operation. By checking the integrity of the packet by comparing the checksum values received from the transmitting node 100 before the packet transmission, it is possible to ensure confidentiality and integrity in data transmission using network coding.

The present invention has been described above with reference to specific embodiments of the present invention, but this is only illustrative and does not limit the scope of the present invention. Those skilled in the art can change or modify the described embodiments without departing from the scope of the present invention. Each of the functional blocks or means described in the present specification may be implemented in a program form, and may be implemented separately, or two or more may be integrated into one. Components such as modules described as separate in the specification and claims may be merely functionally distinct and may be physically implemented by one means, and components such as means described as a single element may be divided into several components. It can be made in combination. In addition, each method step described herein may be changed in order without departing from the scope of the present invention, and other steps may be added. In addition, the various embodiments described herein may be implemented independently as well as each other as appropriate. Therefore, the scope of the invention should be defined by the appended claims and their equivalents, rather than by the described embodiments.

100: transmitting node 102: channel forming unit
104a: transmission packet generator 104b: checksum calculator
104: data processing unit 106: transmission unit
120: intermediate node 140: receiving node

Claims (15)

A security processing system in a network using network coding that collects packets transmitted from a transmitting node at an intermediate node, encodes the packets, and transmits the encoded packets to the receiving node.
The transmitting node,
A channel forming unit configured to share a security key with the receiving node after forming a secure channel with the receiving node;
After dividing the transmission data to be transmitted to the receiving node into blocks, encrypting each block to generate a transmission packet, calculating the checksum value for each encrypted block, and then transmitting the calculated checksum value to the receiving node. A data processing unit
A transmission unit for transmitting the generated transmission packet to the receiving node through the intermediate node;
The receiving node,
After calculating the checksum value for the transport packet received from the transmitting node, the integrity of the received transport packet is checked by comparing the calculated checksum value with the checksum value received from the transmitting node.
Data transmission system in a network using network coding.
The method of claim 1,
Wherein the data processing unit comprises:
After calculating the max-flow value in consideration of the network situation, the max-flow value is set to a block size which is a basic unit of transmission, and the block is divided after the transmission data is divided into the block to fit the set block size. And a transport packet generator for encrypting each of the security keys to generate the transport packet.
Data transmission system in a network using network coding.
The method of claim 1,
Wherein the data processing unit comprises:
The data of each bit in the encrypted block is calculated through calculation with the security key, the value for each bit is added, the value for each calculated bit is added, the checksum value for each block is calculated, and the transmission is performed. A checksum calculator for generating a total checksum value for a packet and transmitting the total checksum value to the receiving node;
Data transmission system in a network using network coding.
The method of claim 1,
The receiving node is a linear between a global operation vector having a linear operation value between actual data and the security key in the received transmission packet and coding information of intermediate nodes through which the transmission packet passes and a checksum value received from the transmitting node. Performing the integrity check by comparing between operation values
Data transmission system in a network using network coding.
The method of claim 1,
The receiving node ignores a packet in which an error occurs as a result of the integrity check, and performs decoding using only packets without errors.
Data transmission system in a network using network coding.
The method of claim 5, wherein
The receiving node transmits information about the packet in which the error occurs to the transmitting node through the secure channel when the number of packets in which the error occurs is greater than or equal to a preset number, and corresponds to the information through the secure channel. Receive a block from the transmitting node and use it for decoding
Data transmission system in a network using network coding.
The method according to claim 6,
The transmitting node encrypts a block corresponding to the information in the transmitting node using the security key and transmits the block to the receiving node.
Data transmission system in a network using network coding.
The method of claim 7, wherein
The receiving node decrypts the encrypted block received from the transmitting node with the security key and then decodes the decrypted block.
Data transmission system in a network using network coding.
A data transmission method in a network using network coding in which packets transmitted from a transmitting node are collected at an intermediate node and then encoded and transmitted to the receiving node,
Establishing a secure channel between the transmitting node and the receiving node to share a security key;
Generating a transmission packet by dividing the transmission data into blocks by the transmitting node and encrypting each block;
Calculating checksum values for each of the encrypted blocks, and transmitting the calculated checksum values to the receiving node;
Transmitting the generated transport packet to the receiving node through the intermediate node;
Checking the integrity of the received transport packet by calculating a checksum value of the transport packet received by the receiving node and then comparing the calculated checksum value with the checksum value received by the transmitting node. doing
Data transmission method in a network using network coding.
The method of claim 9,
Generating the transport packet,
Calculating a max-flow value in consideration of the network situation;
Setting the calculated max-flow value to a block size that is a basic unit of transmission, dividing the transmission data into the blocks so as to meet the set block size;
Encrypting each of the blocks to generate the transport packet;
Data transmission method in a network using network coding.
The method of claim 9,
Performing the integrity check,
Calculating a first value through a linear operation between actual data and the security key in a transmission packet received at the receiving node;
Calculating a second value through a linear operation between a global encoding vector having coding information of intermediate nodes passing through the transport packet and a checksum value received from the transmitting node;
Performing the integrity check through a comparison between the first value and a second value.
Data transmission method in a network using network coding.
The method of claim 9,
The step of transmitting to the receiving node,
The data of each bit in the encrypted block is calculated through calculation with the security key, the value for each bit is added, the value for each calculated bit is added, the checksum value for each block is calculated, and the transmission is performed. Generating a full checksum value for a packet and sending it to the receiving node
Data transmission method in a network using network coding.
The method of claim 9,
The data transmission method,
Ignoring the error-prone packet according to the integrity check result at the receiving node, and decoding using only the error-free packet;
Data transmission method in a network using network coding.
The method of claim 13,
The data transmission method,
Transmitting information on the block that cannot be decoded to the transmitting node through the secure channel when the error occurred packet is more than a preset number;
Receiving a block corresponding to the information from the transmitting node through the secure channel and decoding the block;
Data transmission method in a network using network coding.
15. The method of claim 14,
Receiving over the secure channel and then decoding it,
Encrypting, by the transmitting node, the block corresponding to the information using the security key and transmitting the same to the receiving node;
Decrypting the encrypted block received at the receiving node with the security key;
Performing decoding on the decoded block;
Data transmission method in a network using network coding.

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